Method of introducing a sample into a separation column and corresponding system

ABSTRACT

A method of introducing a sample into a separation column includes introducing the sample into a trap column, isolating the trap column from ambient atmosphere and pressurizing the trap column to a first pressure while the trap column is isolated from ambient atmosphere, providing a fluid connection between the trap column and the separation column after pressurizing the trap column to the first pressure, supplying the sample from the trap column to the separation column.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit under 35 U.S.C. § 119 toGerman Patent Application No. DE 10 2016 121515.5, filed on Nov. 10,2016, the disclosure of which is incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to the field of liquid chromatography (LC)and particularly to high pressure liquid chromatography (HPLC). Theinvention also relates to a sampler for liquid chromatography,especially for high performance liquid chromatography.

BACKGROUND

In LC systems, a liquid sample is introduced with an analytical pumpinto a separation column. Different constituents of the sample adhere tothe separation column in a different manner. A pump pushes a solvent (ordifferent solvents) through the separation column. Depending on, interalia, the adherence of the constituents to the separation column, thesolvent, the flow rate of the solvent and the pressure of the solvent,the different constituents of the sample need different amounts of timeto pass through the separation column; generally, the more strongly aconstituent interacts with the separation column, the longer it willneed to pass through the separation column. This allows the constituents(and thus, the sample) to be determined and analyzed.

Introducing the sample into the separation column typically comprisesdifferent steps including (1) a sample pick up means, such as a needle,being introduced into a sample reservoir and picking up the sample. (2)The sample may then be introduced from the needle into a section forintermediate storing of the sample. Subsequently, (3) the sample may beintroduced from the section for intermediate storing of the sample intothe separation column. For this purpose, injection valves may be used.Such injection valves or distribution valves may connect different portswith one another to establish a fluid connection between different partsor sections of an LC system. For example, U.S. Pat. No. 3,530,721discloses an apparatus for supplying liquid samples into a separationcolumn. The apparatus includes a switch that can be switched from onestate allowing a sample to be drawn into a receptacle (e.g., forcarrying our steps (1) and (2)) to another state allowing the sample tobe pumped from the receptacle into a column (e.g., for carrying out theabove described step (3)). U.S. Pat. No. 4,939,943 discloses an injectorincluding a high pressure syringe unit and a valve unit for LC, whichvalve unit is adapted to assume different positions, one for sample pickup and one for introducing the sample into a chromatographic column.

A further variant of LC systems includes a so-called trap column.Instead of intermediate storing of the sample in a simple section oftubing or in a simple receptacle, the sample may first be introducedinto a trap column and constituents of the sample may adhere to the trapcolumn (which may also be called a “pre-column”). Thus, by means of thetrap column, the sample may be concentrated. In other words, wheninjecting sample into a trap column, the sample is guided with the helpof a pumping device into the trap column (or pre-column), i.e. onto thematerial of the trap column. The sample components remain hanging in thecolumn. The sample can therefore be concentrated. Subsequently, thesample may be entrained in an analytical flow from the trap columnthrough the separation column. Again, switching from the first step(introducing a sample into the trap column) to the second step(providing a flow to introduce the sample from the trap column to theseparation column) may be done by switching of a valve. In other words,after introducing the sample into the trap column, the trap column isconnected with an analytical flow, the sample detaches from the trapcolumn, and is guided into the separation column (which may also bereferred to as an analytical column). The separation of the sample fromthe trap column is enabled by the interaction of the sample with thecolumn and the flow.

That is, in very simple words, a sample is picked up and introduced intoa trap column. The trap column is then fluidly connected to a separationcolumn and the sample is supplied from the trap column to the separationcolumn. The supplying of the sample from the trap column to theseparation column is typically done by means of an analytical pumpproviding a pressure exceeding the atmospheric pressure. In HPLC, thispressure may be on the order of 1000 bar, such as 1500 bar.

However, while the above described prior art may be satisfactory in someinstances, it has several disadvantages and limitations. It has beenfound that the above described method leads to substantial wear of thetrap column and the separation column, thereby deteriorating the resultsof subsequent analyses and/or necessitating an earlier replacement ofthese components or of the complete system. That is, the lifetime of thesystem is negatively affected. Furthermore, it has been found that theabove described method may lead to undesired mixing of the sample withthe solvent (dispersion), thereby also deteriorating the results ofsubsequent analyses.

SUMMARY

It is therefore an object of the invention to overcome or at leastalleviate the shortcomings and disadvantages of the prior art. Moreparticularly, it is an object of the present invention to provide amethod for introducing a sample into a separation column, which methodleads to an increased lifetime of the system and which method leads tobetter analytical results.

These objects are met by the method of the present technology.

According to a first embodiment, these objects are met by a method ofintroducing a sample into a separation column. The method comprisesintroducing the sample into a trap column, isolating the trap columnfrom ambient atmosphere and pressurizing the trap column to a firstpressure while the trap column is isolated from ambient atmosphere,providing a fluid connection between the trap column and the separationcolumn after pressurizing the trap column to the first pressure, andsupplying the sample from the trap column to the separation column.

That is, the sample in the trap column is pressurized before it isintroduced into the separation or analytical column. This may bedifferent to the prior art, where the trap column was connected to theseparation column and then pressurized. That is, in the prior art, whenconnecting the trap column to the analytical pump and to the separationcolumn, the trap column is rapidly brought from a starting pressure(which typically is similar or equal to atmospheric pressure) to anincreased pressure. On the other hand, the separation column istypically at the increased pressure. When fluidly connecting theseparation column to the trap column (which initially is at atmosphericpressure)—as in the prior art—the pressure in the separation column willdip rapidly. That is, by means of the known methods, there is a sharpincrease in pressure in the trap column and a sharp decrease followed bya sharp increase in pressure in the separation column. It has been foundthat these sharp pressure spikes are disadvantageous and that it isadvantageous not to have these pressure spikes, but to bring the trapcolumn to an increased pressure in a more controller manner. This mayreduce wear on the trap column, the separation column and componentsfluidly connected to these components. Furthermore, by preventing orreducing the pressure spikes, the sample may be less dispersed withsolvent, leading to more defined peaks in subsequent analysis, therebyresulting in an improved analysis. All these advantages may be achievedby the present invention, which therefore meets the objects of thepresent invention.

Generally, introducing the sample into the separation column may includeswitching of an injection valve. During switching of such an injectionvalve, compression and decompression volumes flow through the valve witha high speed. These currents can cause damage to the high-pressure valvecomponents. Pressure surges at the columns also lead to high speeds ofthe sample, so that it can inadvertently mix with the flow. Asdiscussed, the present invention relates to a method that enablespre-compressing of the trap column. Pressure surges and associated fastflows are thus avoided. Put differently, in prior art systems, when thetrap column was connected with a pump flow (of an analytical pump), apressure drop or a pressure collapse occurred in the separation column,as the trap column and its connections (e.g., capillaries) were not atthe same pressure as the system. This led to high current speeds (thatcould damage the valve and the columns) which, particularly for analyseswith very small analytical fluxes, were hard to exactly reproduce,thereby also compromising the final analytical results. All this isprevented by the present invention.

That is, the present invention solves problems of a pressure drop bypreemptively bringing the trap column to an elevated pressure, e.g. tosystem pressure. With the help of this invention, the trap column isbrought to system pressure before the injection. This helps avoid strongcurrents at the valve and prevents uncontrolled pressure drop after theinjection, as well as undesirable mixing of the sample with the flow(dispersion).

It will be understood that the sample may be a liquid sample. As willfurther be understood, when the sample is introduced into the trapcolumn, some constituents of the sample will adhere to the trap columnwhile other constituents may not adhere and may flow through the trapcolumn and go to waste (which may also be referred to as a wastereservoir). That is, the sample being introduced and adhering to thetrap column does not necessarily have exactly the same composition asthe original sample. The same applies to the sample which is suppliedfrom the trap column to the separation column. E.g., depending on thetype of solvent used, only some constituents of the sample adhering tothe trap column may be introduced to the separation column. For sake ofbrevity and simplicity of description, however, all of the above willsimply be referred to as “the sample”—although it is clear to theskilled person that the sample originally introduced into a systemcarrying out the described method does not necessarily correspond to100% to the sample that is supplied to the separation column andsubsequently analyzed.

The first pressure may exceed the ambient pressure by at least 10 bar,preferably by at least 100 bar, more preferably by at least 1000 bar,such as by at least 1500 bar.

The method may be carried out by a liquid chromatography system.

The liquid chromatography system may comprise an analytical pump adaptedto provide a flow of pressurized fluid.

The method may also comprises providing a fluid connection between thetrap column and the analytical pump, wherein the fluid connectionbetween the trap column and the analytical pump is providedsimultaneously with providing the fluid connection between the trapcolumn and the separation column. This provides similar benefits as theones discussed above.

The liquid chromatography system may comprise a metering device.

Introducing the sample into the trap column at a first pressure maycomprise the metering device causing a volume of the sample to be suckedinto the liquid chromatography system and the metering device maypressurize the trap column to the first pressure. That is, the meteringdevice may also have the functionality of pressurizing the trap column.By having this functionality incorporated in the metering device, thereis no need for a further pump for introducing the sample into the trapcolumn. Thus, a less complex system is provided by having thefunctionality of the pressurization integrated in the metering device.This may be advantageous as a less complex system needs less space, hasfewer components that can malfunction and may be simpler to service.

The metering device may comprise a first port and a second port forfluidly connecting the metering device to other components and each ofthese ports can selectively be opened and closed.

The liquid chromatography system may comprise a sample pick up means, aseat to receive the sample pick up means and a first distribution valve.

Introducing the sample into the trap column may comprise the sample pickup means being moved to a sample reservoir, the sample being sucked intothe sample pick up means and optionally into a tubing section adjacentto the sample pick up means, the sample pick up means being moved to theseat, the first distribution valve being set to provide a fluidconnection between the seat and the trap column, and the sample beingintroduced into the trap column.

The sample being introduced into the trap column may be done by means ofthe metering device. Again, having this functionality performed by themetering device may omit the necessity of further components, therebyrendering the system less complex and leading to the above describedadvantages.

The method may comprise a solvent being introduced into the meteringdevice through the first port before the sample is introduced into thetrap column, wherein introducing the sample into the trap columncomprises the solvent being expelled from the metering device throughthe second port.

The method may comprise a solvent being introduced into the meteringdevice through the first port after the sample is introduced into thetrap column, and expelling the solvent from the metering device throughthe second port.

When introducing the sample into the trap column, the sample may enterthe trap column in a first flow direction, and, when supplying thesample from the trap column to the separation column, the sample mayleave the trap column in a second flow direction, which second flowdirection is opposite to the first flow direction. This procedure mayalso be referred to as a “backward flush”. As will be understood, somecomponents of the sample will remain at an “entrance” of the trap columnand will be released during the “backward flush” procedure, i.e., thosecomponents will be provided to the separation column without having totravel along a substantial length of the trap column.

Additionally or alternatively, when introducing the sample into the trapcolumn, the sample may enter the trap column in a first flow direction,and, when supplying the sample from the trap column to the separationcolumn, the sample may leave the trap column in the first flowdirection. This procedure may also be referred to as a “forward flush”.That is, any constituent of the sample reaching the separation columnhas travelled through the complete length of the trap column beforereaching in the separation column. This may lead to a highly purifiedsample, which may be advantageous in some regards.

The method may comprise depressurizing the trap column after supplyingthe sample from the trap column to the separation column. In particular,depressurizing the trap column may be done in a controlled manner.Having such a controlled depressurization may be advantageous as itleads to less abrasion on the system components depressurized, preventsfluids from exiting the system rapidly (which could be a safety risk)and reduces the risk of components outgassing in the system.

More particularly, the metering device may depressurize the trap column.Again, having this functionality incorporated in the metering device maybe beneficial, as it may lead to a less complex system.

The liquid chromatography system may comprise a waste.

The method may comprise fluidly connecting the trap column to the wasteand supplying fluid from the trap column to the waste, wherein the trapcolumn and the waste are fluidly connected after the sample is suppliedfrom the trap column to the separation column.

The trap column and the waste may be fluidly connected after the trapcolumn is depressurized. Again, this may lead to a controllerdepressurization with the above described benefits.

The method may comprise solvent being introduced into the meteringdevice through the first port and solvent being expelled from themetering device through the second port after fluidly connecting thetrap column to the waste.

The liquid chromatography system may further comprise a seconddistributor valve, wherein each distributor valve comprises a pluralityof ports and a plurality of connecting elements for changeablyconnecting the ports of the respective distributor valve, wherein asregards the first distributor valve, one port is directly fluidlyconnected to the seat, two ports are directly fluidly connected to thetrap column, one port is directly fluidly connected to the separationcolumn, one port is directly fluidly connected to the analytical pumpand one port is directly fluidly connected to the second distributorvalve; and as regards the second distributor valve, one port is directlyfluidly connected to the first distributor valve, one port is directlyfluidly connected to a waste, one port is directly fluidly connected toa first solvent reservoir and one port is directly fluidly connected tothe metering device.

In this document, a fluid connection (or two elements being fluidlyconnected to one another) means that fluid may flow from one element toanother. A port of a valve being directly fluidly connected to anotherelement should be construed to mean that the port is fluidly connectedto the other element in such a manner that there is no other valve portinterposed between the port of the valve and the other element.

Another port of the second distributor valve may be directly fluidlyconnected to a second solvent reservoir.

The sample pick up means may be a needle.

The liquid chromatography system may comprise a pressure sensor and themethod may comprise the step of the pressure sensor sensing a pressure.This may allow for a particularly controlled pressurization (andoptionally also depressurization) of the trap column.

The pressure sensor may be fluidly connected to the metering device.

The pressure sensor may be arranged between the metering device and thesecond distributor valve.

The present invention also relates to a separation method of separatingconstituents of a sample. The separation method comprises the method ofintroducing a sample into a separation column discussed herein and theseparation method also comprises separating constituents of the samplein the separation column at an analytical pressure, wherein the firstpressure is at least 10% of the maximum analytical pressure, preferablyat least 50%, more preferably at least 90% of the maximum analyticalpressure.

The present invention also relates to a liquid chromatography system.The system comprises a sample pick up means, a metering device fluidlyconnected to the sample pick up means, a seat for receiving the samplepick up means, a trap column, a separation column, an analytical pump, afirst distributor valve comprising a plurality of ports and a pluralityof connecting elements for changeably connecting the ports of the firstdistributor valve, wherein one port is directly fluidly connected to theseat, two ports are directly fluidly connected to the trap column, oneport is directly fluidly connected to the separation column, one port isdirectly fluidly connected to the analytical pump, wherein the system isadapted to assume a configuration, wherein the trap column is isolatedfrom ambient atmosphere and is pressurized to a trap column pressureexceeding ambient pressure without the trap column being fluidlyconnected to the separation column. Again, this may have benefitscorresponding to the ones described above with regard to the method.

The configuration may also be defined by the trap column beingpressurized to the trap column pressure exceeding ambient pressurewithout the trap column being fluidly connected to the analytical pump.

The trap column pressure may exceed ambient pressure by at least 10 bar,preferably by at least 100 bar, more preferably by at least 1000 bar,such as by at least 1500 bar.

The configuration may also be defined by the metering device beingfluidly connected to the trap column.

The system may further comprise a waste, a first solvent reservoir, asecond distributor valve, which second distributor valve comprises aplurality of ports and a plurality of connecting elements for changeablyconnecting the ports of the second distributor valve, wherein one portof the second distributor valve is directly fluidly connected to thefirst distributor valve, one port of the second distributor valve isdirectly fluidly connected to the waste, one port of the seconddistributor valve is directly fluidly connected to the first solventreservoir and one port of the second distributor valve is directlyfluidly connected to the metering device.

The system may further comprise a second solvent reservoir and anotherport of the second distributor valve may be directly fluidly connectedto the second solvent reservoir.

The metering device may comprise a first port and a second port, whereinthe first port is directly fluidly connected to the sample pick up meansand the second port is directly fluidly connected to a port of thesecond distributor valve.

The system may further comprise a pressure sensor.

The pressure sensor may be fluidly connected to the metering device.

The pressure sensor may be located between the metering device and thesecond distributor valve.

The invention is also defined by the following numbered embodiments.

In embodiment one, a method of introducing a sample into a separationcolumn, the method comprising introducing the sample into a trap column,isolating the trap column from ambient atmosphere and pressurizing thetrap column to a first pressure while the trap column is isolated fromambient atmosphere, providing a fluid connection between the trap columnand the separation column after pressurizing the trap column to thefirst pressure, supplying the sample from the trap column to theseparation column.

It will be understood that the sample may be a liquid sample. As willfurther be understood, when the sample is introduced into the trapcolumn, some constituents of the sample will adhere to the trap columnwhile other constituents may not adhere and may flow through the trapcolumn and go to waste (which may also be referred to as a wastereservoir). That is, the sample being introduced and adhering to thetrap column does not necessarily have exactly the same composition asthe original sample. The same applies to the sample which is suppliedfrom the trap column to the separation column. E.g., depending on thetype of solvent used, only some constituents of the sample adhering tothe trap column may be introduced to the separation column. For sake ofbrevity and simplicity of description, however, all of the above willsimply be referred to as “the sample”—although it is clear to theskilled person that the sample originally introduced into a systemcarrying out the described method does not necessarily correspond to100% to the sample that is supplied to the separation column andsubsequently analyzed.

In embodiment two, a method in accordance with the preceding embodiment,wherein the first pressure exceeds the ambient pressure by at least 10bar, preferably by at least 100 bar, more preferably by at least 1000bar, such as by at least 1500 bar.

In embodiment three, a method in accordance with any of the precedingembodiments, wherein the method is carried out by a liquidchromatography system.

In embodiment four, a method in accordance with the precedingembodiment, wherein the liquid chromatography system comprises ananalytical pump adapted to provide a flow of pressurized fluid.

In embodiment five, a method in accordance with the precedingembodiment, wherein the method also comprises providing a fluidconnection between the trap column and the analytical pump, wherein thefluid connection between the trap column and the analytical pump isprovided simultaneously with providing the fluid connection between thetrap column and the separation column.

In embodiment six, a method in accordance with any of the precedingembodiments with the features of embodiment 3, wherein the liquidchromatography system comprises a metering device.

In embodiment seven, a method in accordance with the precedingembodiment, wherein introducing the sample into the trap columncomprises the metering device causing a volume of the sample to besucked into the liquid chromatography system and wherein the meteringdevice pressurizes the trap column to the first pressure.

In embodiment eight, a method in accordance with any of the precedingembodiments with the features of embodiment 6, wherein the meteringdevice comprises a first port and a second port for fluidly connectingthe metering device to other components and wherein preferably each ofthese ports can selectively be opened and closed.

In embodiment nine, a method in accordance with any of the precedingembodiments with the features of embodiment 3, wherein the liquidchromatography system comprises a sample pick up means, a seat toreceive the sample pick up means and a first distribution valve.

In embodiment ten, a method in accordance with the preceding embodiment,wherein introducing the sample into the trap column comprises the samplepick up means being moved to a sample reservoir, the sample being suckedinto the sample pick up means and optionally into a tubing sectionadjacent to the sample pick up means, the sample pick up means beingmoved to the seat, the first distribution valve being set to provide afluid connection between the seat and the trap column, the sample beingintroduced into the trap column.

In embodiment eleven, a method in accordance with the precedingembodiment and with the features of embodiment 6, wherein the samplebeing introduced into the trap column is done by means of the meteringdevice.

In embodiment twelve, a method in accordance with any of the precedingembodiments with the features of embodiment 8, wherein the methodcomprises a solvent being introduced into the metering device throughthe first port before the sample is introduced into the trap column, andwherein introducing the sample into the trap column comprises thesolvent being expelled from the metering device through the second port.

In embodiment thirteen, a method in accordance with any of the precedingembodiments with the features of embodiment 8, wherein the methodcomprises a solvent being introduced into the metering device throughthe first port after the sample is introduced into the trap column, andexpelling the solvent from the metering device through the second port.

In embodiment fourteen, a method in accordance with any of the precedingembodiments, wherein, when introducing the sample into the trap column,the sample enters the trap column in a first flow direction, andwherein, when supplying the sample from the trap column to theseparation column, the sample leaves the trap column in a second flowdirection, which second flow direction is opposite to the first flowdirection.

In embodiment fifteen, a method in accordance with any of the precedingembodiments without the features of the preceding embodiment, wherein,when introducing the sample into the trap column, the sample enters thetrap column in a first flow direction, and wherein, when supplying thesample from the trap column to the separation column, the sample leavesthe trap column in the first flow direction.

In embodiment sixteen, a method in accordance with any of the precedingembodiments, wherein the method comprises depressurizing the trap columnafter supplying the sample from the trap column to the separationcolumn.

In embodiment seventeen, a method in accordance with the precedingembodiment and with the features of embodiment 6, wherein the meteringdevice depressurizes the trap column.

In embodiment eighteen, a method in accordance with any of the precedingembodiments with the features of embodiment 3, wherein the liquidchromatography system comprises a waste.

In embodiment nineteen, a method in accordance with the precedingembodiment, wherein the method comprises fluidly connecting the trapcolumn to the waste and supplying fluid from the trap column to thewaste, wherein the trap column and the waste are fluidly connected afterthe sample is supplied from the trap column to the separation column.

In embodiment twenty, a method in accordance with any of the precedingembodiments with the features of embodiments 16 and 19, wherein the trapcolumn and the waste are fluidly connected after the trap column isdepressurized.

In embodiment twenty-one, a method in accordance with any of the twopreceding embodiments with the features of embodiments 6 and 8, whereinthe method comprises solvent being introduced into the metering devicethrough the first port and solvent being expelled from the meteringdevice through the second port after fluidly connecting the trap columnto the waste.

In embodiment twenty-two, a method in accordance with any of thepreceding embodiments with the features of embodiments 4, 6 and 9,wherein the liquid chromatography system further comprises a seconddistributor valve, wherein each distributor valve comprises a pluralityof ports and a plurality of connecting elements for changeablyconnecting the ports of the respective distributor valve, wherein asregards the first distributor valve, one port is directly fluidlyconnected to the seat, two ports are directly fluidly connected to thetrap column, one port is directly fluidly connected to the separationcolumn, one port is directly fluidly connected to the analytical pumpand one port is directly fluidly connected to the second distributorvalve; and as regards the second distributor valve, one port is directlyfluidly connected to the first distributor valve, one port is directlyfluidly connected to a waste, one port is directly fluidly connected toa first solvent reservoir and one port is directly fluidly connected tothe metering device.

In this document, a fluid connection (or two elements being fluidlyconnected to one another) means that fluid may flow from one element toanother. A port of a valve being directly fluidly connected to anotherelement should be construed to mean that the port is fluidly connectedto the other element in such a manner that there is no other valve portinterposed between the port of the valve and the other element.

In embodiment twenty-three, a method in accordance with the precedingembodiment, wherein another port of the second distributor valve isdirectly fluidly connected to a second solvent reservoir.

In embodiment twenty-four, a method in accordance with any of thepreceding embodiments with the features of embodiment 9, wherein thesample pick up means is a needle.

In embodiment twenty-five, a method in accordance with any of thepreceding embodiments with the features of embodiment 3, wherein theliquid chromatography system comprises a pressure sensor and wherein themethod comprises the step of the pressure sensor sensing a pressure.

In embodiment twenty-six, a method in accordance with the precedingembodiment and with the features of embodiment 6, wherein the pressuresensor is fluidly connected to the metering device.

In embodiment twenty-seven, a method in accordance with any of the twopreceding embodiments and with the features of embodiment 22, whereinthe pressure sensor is arranged between the metering device and thesecond distributor valve.

In embodiment twenty-eight, a separation method of separatingconstituents of a sample, wherein the separation method comprises themethod of introducing a sample into a separation column in accordancewith any of the preceding embodiments and wherein the separation methodalso comprises separating constituents of the sample in the separationcolumn at an analytical pressure, wherein the first pressure is at least10% of the maximum analytical pressure, preferably at least 50%, morepreferably at least 90% of the maximum analytical pressure.

Below, system embodiments will be discussed. These embodiments areabbreviated by the letter “S” followed by a number. When reference isherein made to a system embodiment, those embodiments are meant.

In system embodiment one, a liquid chromatography system comprising asample pick up means, a metering device fluidly connected to the samplepick up means, a seat for receiving the sample pick up means, a trapcolumn, a separation column, an analytical pump, a first distributorvalve comprising a plurality of ports and a plurality of connectingelements for changeably connecting the ports of the first distributorvalve, wherein one port is directly fluidly connected to the seat, twoports are directly fluidly connected to the trap column, one port isdirectly fluidly connected to the separation column, one port isdirectly fluidly connected to the analytical pump, wherein the system isadapted to assume a configuration, wherein the trap column is isolatedfrom ambient atmosphere and is pressurized to a trap column pressureexceeding ambient pressure without the trap column being fluidlyconnected to the separation column.

In system embodiment two, a liquid chromatography system according tothe preceding embodiment, wherein the configuration is also defined bythe trap column being pressurized to the trap column pressure exceedingambient pressure without the trap column being fluidly connected to theanalytical pump.

In system embodiment three, a liquid chromatography system according toany of the preceding system embodiments, wherein the trap columnpressure exceeds ambient pressure by at least 1 bar, preferably by atleast 10 bar, more preferably by at least 100 bar, such as by at least500 bar.

In system embodiment four, a liquid chromatography system according toany of the preceding system embodiments, wherein the configuration isalso defined by the metering device being fluidly connected to the trapcolumn.

In system embodiment five, a liquid chromatography system according toany of the preceding system embodiments, wherein the system furthercomprises a waste, a first solvent reservoir, a second distributorvalve, which second distributor valve comprises a plurality of ports anda plurality of connecting elements for changeably connecting the portsof the second distributor valve, wherein one port of the seconddistributor valve is directly fluidly connected to the first distributorvalve, one port of the second distributor valve is directly fluidlyconnected to the waste, one port of the second distributor valve isdirectly fluidly connected to the first solvent reservoir and one portof the second distributor valve is directly fluidly connected to themetering device.

In system embodiment six, a liquid chromatography system according tothe preceding embodiment, wherein the system further comprises a secondsolvent reservoir and wherein another port of the second distributorvalve is directly fluidly connected to the second solvent reservoir.

In system embodiment seven, a liquid chromatography system according toany of the preceding system embodiments with the features of embodimentsS5, wherein the metering device comprises a first port and a secondport, wherein the first port is directly fluidly connected to the samplepick up means and the second port is directly fluidly connected to aport of the second distributor valve.

In system embodiment eight, a liquid chromatography system according toany of the preceding system embodiments, wherein the system furthercomprises a pressure sensor.

In system embodiment nine, a liquid chromatography system according tothe preceding embodiment, wherein the pressure sensor is fluidlyconnected to the metering device.

In system embodiment ten, a liquid chromatography system according toany of the preceding two embodiments and with the features of embodimentS5, wherein the pressure sensor is located between the metering deviceand the second distributor valve.

BRIEF DESCRIPTIONS OF DRAWINGS

The present invention will now be described with reference to theaccompanying drawings which illustrate embodiments of the invention,without limiting the scope of the invention.

FIG. 1 depicts a liquid chromatography system of a first embodimentaccording to the present invention in a first configuration;

FIG. 2 depicts components of a distributor valve employed in embodimentsof the present invention;

FIG. 3 depicts the system of FIG. 1 in a second configuration (which maybe referred to as the “idle state”);

FIG. 4 depicts the system of FIG. 1 in a third configuration (which maybe referred to as the “sample pick up state”);

FIG. 5 depicts the system of FIG. 1 in a fourth configuration (which maybe referred to as the “trapping state”);

FIG. 6 depicts the system of FIG. 1 in a fifth configuration (which maybe referred to as the “pre-pressurize state”);

FIG. 7a depicts the system of FIG. 1 in a sixth configuration (which maybe referred to as the “backward flush injection state”);

FIG. 7b depicts the system of FIG. 1 in a seventh configuration (whichmay be referred to as the “forward flush injection state”);

FIG. 8 depicts the system of FIG. 1 in an eighth configuration (whichmay be referred to as the “de-pressurize state”); and

FIG. 9 depicts the system of FIG. 1 in a ninth configuration (which maybe referred to as the “washing state”).

It is noted that not all of the drawings carry all the reference signs.Instead, in some of the drawings, some of the reference signs have beenomitted for sake of brevity and simplicity of illustration.

DETAILED DESCRIPTIONS OF EMBODIMENTS

FIG. 1 schematically depicts a liquid chromatography (“LC”) system 1000in accordance with an embodiment of the present technology. Inparticular, the liquid chromatography system 1000 can be a high pressureliquid chromatography system 1000 (also referred to as a highperformance liquid chromatography system 1000 or abbreviated HPLCsystem), that is a system adapted to be employed with pressuresexceeding 100 bar, preferably exceeding 1.000 bar, such as 1.500 bar. Toperform a LC, in essence, a sample contained in a sample container orsample reservoir 2 has to be transferred into a separation column 4.Different constituents of the sample adhere differently to theseparation column 4. Thus, when an analytical pump 12 causes the sampleto flow through the separation column 4, the different constituents ofthe sample will leave the separation column 4 at different times,allowing the constituents to be subsequently detected.

The present technology is particularly directed to introducing thesample into the separation column 4. In essence, this is achieved by asample pick up means 8 (such as a needle 8) of the LC system 1000 beinginserted into the sample reservoir 2 (see FIG. 4) and a suction beingsupplied to a tubing 510 connecting the needle 8 and a metering device100. Such suction can be supplied to said tubing 510 by a piston 106 ofthe metering device 100 retracting out of a housing 108 of the meteringdevice 100. Thus, a sample can be sucked from the sample reservoir 2into the needle 8. It may also be sucked into a tubing end section 512,which tubing end section 512 is adjacent to the needle 8. The tubing endsection 512 may also be referred to as sample loop 512. The needle 8 cansubsequently be seated into a seat 10 which will also be referred to asa needle seat 10 (see FIG. 5), and the sample can be pushed onto a trapcolumn 6 by the piston 106 of the metering device 100 being movedforward. By switching a distributor valve 200 into an appropriateposition (see the alternatives of FIGS. 7a and 7b ), the trap column 6can be fluidly connected to the separation column 4. In such a state,the analytical pump 12 can cause the sample to flow from the trap column6 to the separation column 12.

In the above, the general setup of one embodiment of the presenttechnology has been described. The described trap column 6 may be ofsome relevance for the present technology. The trap column 6 is used topreconcentrate the sample: Instead of injecting the sample directly intothe separation column, the sample is first guided to the trap column 6,where the constituents to be analyzed may adhere. These constituents maythen be separated for further assessment by an appropriate fluid beingpumped through the trap column 6 by means of the analytical pump 12. Itwill be understood that when introducing the sample from the trap column6 into the separation column 4, the sample and the section of the system1000 being fluidly connected to the separation column 4 will be atanalytical pressure, i.e. at the pressure at which the separation isperformed. As discussed, this may be a pressure of several hundred bar,or even a pressure exceeding 1.000 bar. It will be understood that afterthe sample has been introduced into the trap column 6 (see FIG. 5), thetrap column 6 is typically not yet at the analytical pressure. Instead,in this state (see FIG. 5), the section of the system 1000 being fluidlyconnected to the trap column 6 comprises the following: metering device100, tubing 510 connecting the metering device 100 to the needle 8,needle 8, trap column 6, tubing 520 connecting distributor valves 200and 400 and waste 18. In this section and in this state orconfiguration, there may be atmospheric or ambient pressure, i.e. apressure sufficiently below the analytical pressure.

In principle, after the sample has been transferred into the trap column6 (see FIG. 5) and onto the material in the trap column 6, one couldimmediately switch the system 1000 to one of the states depicted inFIGS. 7a and 7b , that is to a state where the sample is transferredfrom the trap column 6 to the separation column 4. Thus, the pump 12would have to bring the trap column 6 and the separation column 4 to theanalytical pressure.

However, in the depicted embodiment of the present technology, the trapcolumn 6 is pressurized before it is fluidly connected to the separationcolumn 4. This is depicted in FIG. 6. Here, the section of the system1000 being fluidly connected to the trap column 6 comprises thefollowing: metering device 100, tubing 510 connecting the meteringdevice 100 to the needle 8, needle 8, trap column 6, tubing 520connecting distributor valves 200 and 400. However, in contrast to theconfiguration depicted in FIG. 5, the tubing 520 is not connected to thewaste 18. Instead, the distributor valve 400 is set such that tubing 520includes a “dead end”. Put differently, trap column 6 is connected todead ends at both sides. Put differently still, trap column 6 isisolated from the ambient atmosphere. In this state, the piston 106 ofthe metering device 100 may be moved forward to pressurize the sectionof the system 1000 being fluidly connected to the trap column 6 andhence also the trap column 6. Thus, this section may be brought to anelevated pressure and particularly to the analytical pressure before thetrap column 6 is fluidly connected to the separation column 4. This maybe advantageous for various reasons: The trap column 6 may be brought toan elevated pressure (e.g., to the analytical pressure) in a controlledmanner, thereby preventing pressure spikes at the trap column 6 thatcould occur otherwise and that could damage the trap column. Further,the separation column 4 can be maintained at elevated pressures (e.g.,at the analytical pressure). That is, instead of having to pressurizeboth the trap column 6 and the separation column 4 after these twocolumns have been fluidly connected to one another, the trap column 6 isconnected to the separation column 4 when both of them are pressurized.This also prevents the separation column 4 from being subjected topressure alterations and pressure spikes. This may reduce the wear onthe components and increase the lifetime of the components and theoverall system. Further, not having pressure spikes also reduced thelikelihood of the sample being mixed with solvent, i.e., dispersion.Having a less dispersed sample leads to a more defined peak insubsequent analysis, thereby resulting in an improved analysis.

FIG. 1 also depicts blind plugs 230, 430. In the embodiments depicted inFIG. 1, valve 200 comprises one bling plug 230 and valve 400 comprisestwo blind plugs 430. Blind plugs 230, 430 may be used to close off portsin the distributor valves 200, 400. Thus, the distributor valves 200,400 may be identical to one another (and only differ by the use of theblind plugs 230, 430), which may simplify the productions process. Moreparticularly, in the embodiment depicted in FIG. 1, each distributionvalve 200, 400 comprises 7 ports, however, two ports of the rightdistribution valve 400 and one port of the left distribution valve 200are closed off by the discussed bling plugs 230, 430.

The system 1000 may also comprise a pressure sensor 20. The pressuresensor 20 may be fluidly connected to the metering device 100 (e.g., itmay be disposed between metering device 100 and the second switchingvalve 400). Thus, when precompressing a section of the system 1000 (asdiscussed), one may monitor the pressure in this section—e.g., to bringthis pressure to the analytical pressure. The sensor 20 may also be usedfor monitoring the decompression of a section of the system.

The embodiment of the present technology depicted in the Figures willnow be described in greater detail. FIG. 1 depicts the liquidchromatography system 1000. The system comprises a sample reservoir 2including a sample to be analyzed, a trap column 6, a separation column4, an analytical pump 12, a metering device 100, a sample pick up means8 (which is here realized as a needle 8), a seat 10 (which is hererealized as a needle seat 10), solvent reservoirs 14, 16, a waste 18,tubing interconnecting different elements of the system 1000, as well astwo distributor valves 200, 400. The distributor valves 200, 400 can beset to different states to switch the connection between differentelements. One exemplary realization of a distributor valve 200 isdepicted in FIG. 2. Each distributor valve 200 may comprise a stator 210and a rotor 220. The stator 210 may comprise ports 212 to whichdifferent elements may be connected (e.g., in the embodiment depicted inFIG. 1, each of the needle 8, the analytical pump 12, the separationcolumn 4 and the tubing 520 to the other distribution valve 400 isfluidly connected to one port of the distributor valve 200,respectively, and the trap column 6 is fluidly connected to two ports ofthis distributor valve 200). The rotor 220 may comprise connectingelements 222, such as grooves 222, that may interconnect different ports212 of the stator element 210. For example, FIG. 1 depicts aconfiguration where each connecting element 222 of the rotor of the leftdistribution valve 200 interconnects two ports of said distributionvalve, respectively, while the stator and the rotor of the seconddistribution valve 400 are in such a configuration that none of theports in the second distribution valve are connected to one another. Itwill be understood that whenever two elements are described to beconnected to one another, this denotes a fluid connection, i.e., aconnection where a fluid may flow from one element to the other, unlessotherwise specified or unless clear to the skilled person that somethingdifferent is meant.

In FIG. 1, the system or setup 1000 in an idle position: flow of theanalytical pump 12 is passed through the first valve 200 directly to theseparation column 4. The needle 8 is in the needle seat 10. The rightvalve 400, which valve 400 is responsible for the selection of trapfluids and for providing the Compress position, is set here to“Compress”. That is, the valve 400 is set such that the tubing section520 connecting the first valve 200 to the second valve 400 includes a“dead end”.

FIG. 3 depicts how the metering device 100 may get filled with a firstportion of trap solvent. The metering device 100 has two connectionports 102, 104, which are also referred to as first connection port 104and second connection port 102. The right valve 400 connects port 102 ofthe metering device 100 (which port 102 may also be referred to as aninput) with a solvent reservoir 14. The other side, i.e., the otherconnection port 104 of the metering device 100 is closed over the tubing510 connecting the metering device 100 and the needle 8, which tubing510 may include a buffer loop 514, the needle seat 10, the trap column6, the first valve 200, tubing 520 and the second valve 400. The bufferloop 514 may provide an additional length of tubing to allow movement ofthe needle 8. In the depicted position, the piston 106 of the meteringdevice 100 can pull back while raising solvent from solvent reservoir14. It is noted that valve 2 may also be switched to such a positionthat, instead, solvent may be supplied from solvent reservoir 16 to themetering device 100. That is, in simple words, FIG. 3 depicts aconfiguration where trap solvent may be supplied to the metering device100 from solvent reservoir 14. Furthermore, there may also be a fluidflow from the analytical pump 12 through the separation column in thisconfiguration.

FIG. 4 depicts a configuration where the right valve 400 again entersthe compress position, i.e., the state where the metering device 100 isclosed at port 104, i.e. where this port 104 is connected to a dead end.More particularly, in the configuration depicted in FIG. 4, the tubing520 interconnecting the valves 200 and 400 includes a dead end. Themetering device 100 is first closed at both ports 102, 104, or, in otherwords, in the front and in the back—that is, both ports 102, 104 areconnected to “dead ends”. The needle 2 may be moved to the samplereservoir 2 and the port 102 of the metering device 100, which port 102connects the metering device to the tubing 510, may be opened—i.e. thetubing 510 does no longer lead to a dead end, but to sample reservoir 2.That is, the metering device 100 may be opened via the buffer loop 514.As the piston 106 of the metering device 100 moves back, the sample isdrawn up into needle 8 and optionally also into the tubing section 512adjacent to the needle 8.

FIG. 5 depicts how after the sample is drawn, the needle 8 returns tothe needle seat 10. The right valve 400 connects a side of the trapcolumn 6 facing away from the sample with the waste 18. In thisposition, the piston 106 of the metering device 100 can move forward andtherefore push the sample with the previously raised trap solvent to thetrap column 6. Components which do not adhere to the trap column 6 getpushed out to waste 18. This process may be repeated if the right valve400 again connects the port 104 (which may also be referred to as therear output) of the metering device 100 with the solvent reservoirs 14or 16 and therefore allows the metering device 100 to raise fresh trapsolvent. That is, more trap solvent may be introduced into the sectionof the system fluidly connected to the trap column 6 in FIG. 5. To doso, valve 400 is moved to connect tubing 530 to solvent reservoir 14 or16 (that is the configuration of valve 400 in FIG. 3), thereby “opening”port 104, which is no longer connected to a dead end, and port 102 ofmetering device 100 is “closed” (i.e., it is connected to a dead end).When the piston 106 is moved back in such a configuration, solvent isdrawn from the solvent reservoir 14 (or 16) into the metering device100. Subsequently, port 104 can be closed (i.e., connected to a deadend) and port 102 be opened (i.e., not connected to a dead end). Then,piston 106 may be moved forward to supply the solvent into tubingsection 510 to thereby supply more solvent (and potentially also moresample if there are any residues in the tubing) towards the trap column6. This process may also be referred to as trapping (and retrapping) thesample.

FIG. 6 depicts the configuration where the sample that has been trappedon the trap column 6 and the components that are fluidly connected tothe trap column 6 are pressurized (or “precompressed”). The right valve400 switches back to the compress position, i.e., to the position wheretubing 520 has a dead end. The piston 106 in the metering device 100moves forward, such that volume in the tubing 510 (which includes thebuffer loop 514), the trap column 6, the metering device 106 and theconnections is compressed. It can be compressed until analyticalpressure is reached. By this step, the sample in the trap column 6 maybe brought to an elevated pressure, such as to the analytical pressure.

The trap column 6 may now be fluidly connected to the analytical pump 12on one side and to the separation column 4 on the other side. This maybe done in different ways, depicted in FIGS. 7a and 7b , respectively.

FIG. 7a depicts a configuration, which may be referred to as the“backward flush” configuration. The left valve 200 is switched such thatthe trap column 6 is introduced into the analytical flow in such a waythat the analytical flow pushes the sample back out the side it camefrom (backward flush). That is, the flow direction through the trapcolumn 6 is opposite to the flow direction with which the trap column 6was supplied with the sample. Put differently, a first end of the trapcolumn 6 that has been upstream to a second end of the trap column 6when being provided with the sample is now downstream to this second endwhen the analytical flow is provided through the trap column 6.

Alternatively, as depicted in FIG. 7b , the analytical flow can push thesample further in the direction of the trap flow (forward flush). Thatis, the flow direction through the trap column 6 is parallel to the flowdirection with which the trap column 6 was supplied with the sample. Putdifferently, a first end of the trap column 6 that has been upstream toa second end of the trap column 6 when being provided with the sample isnow also upstream to this second end when the analytical flow isprovided through the trap column 6.

FIG. 8 depicts a configuration similar to the configuration depicted inFIG. 6. Again, the trap column 6 is fluidly connected to the tubing 520connecting valves 200 and 400 and to the tubing 510 (including thebuffer loop 514) providing a connection to the metering device 100. Bymoving the piston 106 back, the pressure still present in the portion ofthe system 1000 fluidly connected to the trap column 6 (including thebuffer loop 514, the metering device 100 and the connections) can bereduced. That is, this configuration may also be referred to as thedecompress state. The controlled decompression may be advantageous fordifferent reasons. By means of the controlled decompression, nouncontrolled and more rapid decompression occurs. Thus, the controlleddecompression leads to less abrasion on the valve 200 and othercomponents and also prevents fluid from rapidly exiting the system(which could be a risk for a user). Furthermore, the controlleddecompression also lowers the risk of components outgassing in the fluidin the system.

FIG. 9 depicts a configuration where the trap column 6 is fluidlyconnected to the waste 18. In this state, if any residual pressureremains in the trap column 6 and the components fluidly connectedthereto, it can be dissipated. That is, in comparison to FIG. 8, theright valve 400 can be switched to waste 18. This state may also bereferred to as the equilibrium phase. The right valve 200 can reconnectthe metering device 100 with solvent reservoir 14 or 16 from thisposition, draw up the respective solvent, and thus wash the trap column6 and components fluidly connected thereto (including the buffer loop514, the needle seat 10 and the trap column 6). That is, the meteringdevice 100 may also be used to wash the system 1000. The washing istypically done iteratively with the configurations depicted in FIGS. 3and 9. That is, the left valve 200 remains in one position and the rightvalve is iteratively switched. In the state depicted in FIG. 3, solventmay be drawn into the metering device and in the state depicted in FIG.9, the components fluidly connected to the metering device 100 (alsoincluding the trap column 6) may be washed. Furthermore, it will beunderstood that washing an equilibrating may be performedsimultaneously. Equilibrating may be done by means of the first (left)valve 200 by having the analytical pump 12 fluidly connected with theseparation column 4 (i.e., valve 200 may not be switched whenequilibrating) and the second (right) valve 400 being iterativelyswitched, as discussed.

Whenever a relative term, such as “about”, “substantially” or“approximately” is used in this specification, such a term should alsobe construed to also include the exact term. That is, e.g.,“substantially straight” should be construed to also include “(exactly)straight”.

Whenever steps were recited in the above or also in the appended claims,it should be noted that the order in which the steps are recited in thistext may be accidental. That is, unless otherwise specified or unlessclear to the skilled person, the order in which steps are recited may beaccidental. That is, when the present document states, e.g., that amethod comprises steps (A) and (B), this does not necessarily mean thatstep (A) precedes step (B), but it is also possible that step (A) isperformed (at least partly) simultaneously with step (B) or that step(B) precedes step (A). Furthermore, when a step (X) is said to precedeanother step (Z), this does not imply that there is no step betweensteps (X) and (Z). That is, step (X) preceding step (Z) encompasses thesituation that step (X) is performed directly before step (Z), but alsothe situation that (X) is performed before one or more steps (Y1), . . ., followed by step (Z). Corresponding considerations apply when termslike “after” or “before” are used.

While in the above, a preferred embodiment has been described withreference to the accompanying drawings, the skilled person willunderstand that this embodiment was provided for illustrative purposeonly and should by no means be construed to limit the scope of thepresent invention, which is defined by the claims.

What is claimed is:
 1. A method of introducing a sample into aseparation column, the method comprising: introducing the sample into atrap column; isolating the trap column from an ambient atmosphere andpressurizing the trap column to a first pressure while the trap columnis isolated from the ambient atmosphere; providing a fluid connectionbetween the trap column and the separation column after pressurizing thetrap column to the first pressure; and supplying the sample from thetrap column to the separation column, wherein the method is carried outby a liquid chromatography system, the liquid chromatography systemcomprising a metering device, in which the metering device pressurizesthe trap column to the first pressure while the trap column is isolatedfrom the ambient atmosphere, and wherein the introducing the sample intothe trap column comprises: sucking a volume of the sample into theliquid chromatography system with the metering device.
 2. The methodaccording to claim 1, wherein the first pressure exceeds the ambientpressure by at least 10 bar.
 3. The method according to claim 1, whereinthe first pressure exceeds the ambient pressure by a value ranging from10 bar to 1500 bar.
 4. The method according to claim 1, wherein theintroducing the sample into the trap column includes adheringconstituents of the sample to the trap column.
 5. The method accordingto claim 1 further comprises: providing a fluid connection between thetrap column and an analytical pump, wherein the fluid connection betweenthe trap column and the analytical pump is provided simultaneously withproviding the fluid connection between the trap column and theseparation column.
 6. The method according to claim 1, wherein themetering device comprises a first connection port and a secondconnection port, the first connection port and the second connectionport both being configured to fluidly connect the metering device toother components of the liquid chromatography system.
 7. The methodaccording to claim 1, wherein the liquid chromatography systemcomprises: a needle; a seat configured to receive the needle; and afirst distribution valve; and wherein the step of introducing the sampleinto the trap column further comprises: moving the needle to a samplereservoir; sucking the sample into the needle from the sample reservoirand optionally sucking the sample into a tubing section adjacent to theneedle; moving the needle to the seat; setting the first distributionvalve to provide a fluid connection between the seat and the trapcolumn; and pushing the sample into the trap column.
 8. The methodaccording to claim 7, in which the step of providing the fluidconnection between the trap column and the separation column comprisessetting the first distribution valve to a flush configuration.
 9. Themethod according to claim 1, wherein the step of pushing the sample intothe trap column with the metering device.
 10. The method according toclaim 8, in which the first distribution valve comprises: a plurality ofports and a plurality of connecting elements configured to changeablyconnect the plurality of ports of the first distribution valve, theplurality of ports of the first distribution valve comprises: a firstport directly fluidly connected to the seat; a second port and a thirdport that are both directly fluidly connected to the trap column; afourth port directly fluidly connected to the separation column; a fifthport directly fluidly connected to the analytical pump; and a sixth portdirectly fluidly connected to a second distributor valve; wherein theliquid chromatography system further comprises the second distributorvalve, wherein the second distributor valve includes a plurality ofports and a plurality of connecting elements configured to changeablyconnect the ports of the second distributor valve, the plurality ofports of the second distribution valve comprises: a seventh portdirectly fluidly connected to the first distributor valve; an eighthport directly fluidly connected to a waste; a ninth port directlyfluidly connected to a first solvent reservoir; and a tenth portdirectly fluidly connected to the metering device.
 11. The methodaccording to claim 1, wherein the step of introducing the sample intothe trap column comprises: flowing the sample into the trap column in afirst flow direction, and wherein the step of supplying the sample fromthe trap column to the separation column comprises: flowing the sampleleaving the trap column in a second flow direction, in which the secondflow direction is opposite to the first flow direction.
 12. The methodaccording to claim 1, wherein the step of introducing the sample intothe trap column comprises: flowing the sample into the trap column in afirst flow direction, and wherein the step of supplying the sample fromthe trap column to the separation column comprises: flowing the sampleleaving the trap column in the first flow direction.
 13. The methodaccording to claim 1, wherein the method comprises: depressurizing thetrap column with the metering device after supplying the sample from thetrap column to the separation column.
 14. A liquid chromatography systemcomprising A) a needle, B) a metering device configured to be fluidlyconnected to the needle; C) a seat configured to receive the needle; D)a trap column; E) a separation column; F) an analytical pump; G) a firstdistributor valve comprising: a) a plurality of ports; and b) aplurality of connecting elements configured to changeably connect to theplurality of ports of the first distributor valve, wherein the pluralityof ports of the first distributor valve comprises: i) a first portdirectly fluidly connected to the seat; ii) a second port and a thirdport that are both directly fluidly connected to the trap column; iii) afourth port directly fluidly connected to the separation column; iv) afifth port directly fluidly connected to the analytical pump; whereinthe liquid chromatography system is configured to isolate the trapcolumn from an ambient atmosphere and to pressurize the trap column withthe metering device to a pressure exceeding the ambient pressure withoutthe trap column being fluidly connected to the separation column, andwherein the liquid chromatography system is configured to suck a volumeof a sample into the liquid chromatography system with the meteringdevice.
 15. The liquid chromatography system according to claim 14,wherein liquid chromatography system is configured to isolate the trapcolumn from an ambient atmosphere and to pressurize the trap column to apressure exceeding the ambient pressure without the trap column beingfluidly connected to the separation column and without the trap columnbeing fluidly connected to the analytical pump.
 16. The liquidchromatography system according to claim 14, wherein the plurality ofports of the first distribution valve further comprises a sixth portdirectly fluidly connected to a second distributor valve; the liquidchromatography system further comprises: H) a waste; I) a first solventreservoir; J) the second distributor valve comprising: a) a plurality ofports and b) a plurality of connecting elements configured to changeablyconnect the ports of the second distributor valve, wherein the pluralityof ports of the second distribution valve comprises: i) a seventh portdirectly fluidly connected to the first distributor valve; ii) an eighthport directly fluidly connected to the waste; iii) a ninth port directlyfluidly connected to the first solvent reservoir; and iv) a tenth portdirectly fluidly connected to the metering device.
 17. The liquidchromatography system according to claim 14, wherein the metering devicecomprises a first connection port and a second connection port, whereinthe second connection port of the metering device is fluidly connectedto the needle and the first connection port is fluidly connected to thetenth port of the second distributor valve.